1. Field of the Invention
The present invention relates to an escape light instrument for guiding people to emergency exits, shelters or the like in the event of an emergency such as a fire or an earthquake.
2. Related art of the Invention
Recently, large underground shopping malls and large buildings are increasing every year, and should a fire arise in such a place, the people present there would be psychologically shocked even more seriously than in a conventional building. In this connection, the importance of fire prevention and fire fighting is pointed out in many quarters. One of the factors having particularly contributed to this awareness may be the tremendous social impact of tragic press reports on the victims of fires involving large structures until 1965.
It was under such a circumstance that the Japanese Fire Service Law was revised to require specified objects of fire prevention, including high-rise buildings, to be equipped with large and medium-size escape lights which excel in visibility over conventional ones in order to take fast refuge when a fire arises. As a result, the newly installed escape lights have proved more effective, but their aesthetic disharmony with the interior designs of buildings is often criticized, and their improvement is urged in this respect.
To meet this requirement, research and development attempts have been undertaken to work out escape lights with smaller sign faces with the finding that the conspicuity of an escape light is determined by the product of the brightness and square measure of the sign face, and accordingly it is now urged to increase the luminance of the sign face in order to make such small escape lights available for practical use.
FIG. 9 illustrates the configuration of an escape light instrument.
The sign face of an escape light panel 1 comprises a white part 1a, which presents the background color, and a green part 1b, on which a guidance sign is drawn. Behind the sign face of the escape light panel 1 is arranged a fluorescent lamp 2, which serves as the light source, in a body 3.
The fluorescent lamp 2 in conventional use would be a white fluorescent lamp for general illumination use, and the spectral characteristics of such a white fluorescent lamp are designed so as to evaluate the fidelity of subtle color reproduction for various kinds of colors for a reference light source (blackbody radiation, synthetic daylight) according to the general color rendering index (Ra).
More specifically, by making the lights of visible wavelength bands the emission spectrum of bi-wavelength emission type concentrated on the bi-wavelength bands such fluorescent lamps include a white fluorescent lamp having a wide band type emission spectrum (hereinafter called a "white fluorescent lamp (FL-W)") and a tri-band type fluorescent lamp having a tri-band type emission spectrum (hereinafter called a "tri-band type fluorescent lamp (EX-N)").
However, the white fluorescent lamp (FL-W) or tri-band type fluorescent lamp (EX-N) mentioned above has a content of a superfluous wavelength band for the discrimination of white and green the discrimination of which is required for any escape light instrument. Therefore when these lamps are used as the light source of the escape light instrument, light flux(luminous efficiency [lm/W]) for supplied power is small.